1. Field of Invention
The invention relates to electric plugs and more particularly to an improved waterproof electric plug having a transformer.
2. Description of Related Art
Alternating-current (AC) power is required to transform into direct current (DC) power prior to supplying to small electric or electronic products such as mobile phones, lamps, Christmas lamp strings, etc. For example, plugs of Christmas lamp strings are required to be waterproof because in often times they are used outsides. Rain, water, and moisture may enter plugs that are not waterproof when the plugs are used outsides. This can cause short circuit to the plugs.
However, many types of waterproof electric plugs having a transformer for Christmas lamp strings have complicated components and poor quality. For example, as shown in FIGS. 1 and 2, a conventional electric plug comprises a housing 10, two prongs 102 on a front surface of the housing 10, a closed groove 103 on a rear end, and two opposite slots 104 on a rectangular flange at the rear end of the housing 10; a cap 13 including a closed protrusion 131 on an edge facing the housing 10 and two opposite projections 132, a closed waterproof strip 12 made of elastomeric material complimentarily disposed in the trough 131, and a transformer 11 disposed in an internal space 101 of the housing 10. In an assembled state of the electric plug the projections 132 are inserted through the slots 104 by snapping, and the protrusion 131 is disposed in the trough 131 to urge against the strip 12.
However, the strip 12 may suffer elastic fatigue as time evolves. Thus, such configured plugs may be not waterproof as desired. Further, portions of the projections 132 are exposed and it is visually unaesthetic.
Thus, the need for improvement still exists.